- Process for preparing 1,1-disubstituted ethylenic monomers
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The present invention relates to a process for preparing 1,1-disubstituted ethylene monomers having general formula (I) from a compound of general formula (II) and an active methylene compound of general formula (III) using a catalytic amount of an ammonium or iminium salt in homogeneous phase or supported on a solid substrate. Said process allows the direct synthesis of the monomers and finds application in the preparation of a wide variety of monomers. The products obtained are reactive monomers of high purity which find application in the field of fast curing adhesives.
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Paragraph 0092; 0106
(2015/11/16)
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- PROCESS FOR PREPARATION OF ALKYL AND ALCOXYALKYL-α-CYANOACRYLATES BY DEPOLYMERISATION OF POLY(ALKYL-α CYANOACRYLATES) OR POLY(ALCOXYALKYL-α-CYANOACRYLATES) AND ITS USAGE AS TECHNICAL AND/OR MEDICAL ADHESIVE
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This invention is related to the preparation of alkyl or alcoxyalkyl-α-cyanoacrylates in monomeric form by depolymerisation of the corresponding poly(alkyl-α-cyanoacrylates) or poly(alcoxyalkyl-α-cyanoacrylates) (PCA). The PCA's are obtained preferably by base-catalyzed condensation of a cyanoacetate with formaldehyde (or a polymer of the latter). According to the invention, the poly(alkyl-α-cyanoacrylate) or poly(alcoxyalky-α-cyanoacrylate), the condensation product, is mixed with a depolymerisation system comprising phosphorus pentoxide P2O5, hydroquinone, ortho-phosphoric acid and para-toluenesulfonic acid. This process is realized in a batch reactor fitted with a condenser, heated at a temperature in the range of 100-300oC, under a vacuum of 0.5-50 Torr (7.10-5 - 7.10-3 MPa) and gives rise to monomeric alkyl-α-cyanoacrylates or monomeric alcoxyalkyl-α-cyanoacrylates, being stable in both gaseous and liquid phase. After an additional purification by vacuum distillation, these cyanoacrylates can be used as fast setting technical or medical adhesives.
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Page/Page column 5-6
(2008/06/13)
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